Protection of groundwater in relation to waste disposal in Wessex water authority

Abstract

Wessex Water Authority, as one of the 10 water authorities of England and Wales, has the responsibility of liaising with Waste Disposal Authorities, that is the County Councils, to ensure that the water resources both groundwater and surface water are not polluted by waste disposal activities. The general policy adopted by Wessex in waste disposal liaison is to discourage waste disposal sites on aquifers. However, taking a realistic view on the subject and bearing in mind that a very large proportion of Wessex area is aquifer outcrop and the need to balance all interests, sites on aquifers are not ruled out automatically. All sites are looked at individually with all advantages and disadvantages being considered and if adequate reliable evidence can be provided to show that a site will not have a detrimental effect on a particular aquifer then the site would be accepted if the need was sufficiently great. This practical approach has been generally well accepted by all parties involved in Wessex and it has resulted in a wide variety of types of site and mechanisms employed to protect both surface water and groundwater. Three sites are described which represent very different circumstances. One is a large site in an isolated area of Carboniferous Limestone for which the proposed technique is to control groundwater levels around the site to ensure inflow to the top rather than outflow. The collected groundwater and leachate is then discharged to a sewer for treatment. A different approach used at a site on Forest Marble which is a fairly clayey material, which although used for small private supplies is not used for major public water supply sources to any significant degree, has been to line the site with a butyl rubber lining in order to contain the leachate and then dispose for treatment. The next approach considered is the acceptance of the dilute and disperse approach at an existing site on chalk; a limestone aquifer which is extremely permeable due to a profusion on inter connected fissures. Finally a proposed site at a non-aquifer site is described which avoids many of the problems encountered at sites situated on aquifers where groundwater has to be protected. The general conclusion reached is that waste disposal requires a flexible approach which results in a wide range of types of site. Such an approach can prevent many problems that can be caused by too rigid an approach.